Designation of the cable on the electrical diagram. Conventional designation in electrical circuits. Conditional graphic and alphabetic designations. Designation of measuring instruments and radio components
INTERSTATE STANDARD
Unified system of design documentation
RULES FOR DRAWING HARNESSES, CABLES AND WIRES
Unified system for design documentation.
Rules for making drawings of braids, cables and wires
Introduction date 01.01.77
APPROVED AND INTRODUCED BY Resolution State Committee standards of the Council of Ministers of the USSR dated November 26, 1975 No. 3618
INSTEAD OF GOST 2.414-68
EDITION (January 2002) with Amendment No. 1 approved in July 1980 (IUS 10-80)
1. This standard establishes the rules for the implementation of drawings of bundles, cables and wires in the design documentation of products in all industries.
The standard fully complies with ST SEV 649-77.
Notes:
1. A harness drawing is an assembly drawing of a specified product, consisting of two or more insulated conductors (wires, cables) fastened into a bundle by interlacing, tying (thread, tape) or in some other way, and, if necessary, others constituent parts(connectors, lugs, etc.).
2. A drawing of a cable (wire) is:
drawing of a part made from one piece of material (cable or wire) indicated in the main inscription of the drawing;
assembly drawing of a specified product, consisting of one cable or wire in the form of a part or material and any other components (connectors, lugs, etc.).
(Revised edition, Rev. No. 1).
2. Drawings of bundles, cables and wires must be made in accordance with the requirements of standards, unified system design documentation and this standard.
3. In the drawings of bundles, cables and wires, individual conductors should be depicted in a simplified way, i.e. external outlines (Fig. 1, a), or conditionally, i.e. one line (Fig. 1, b). With a simplified image of conductors, it is allowed to highlight them graphically according to the example shown in Fig. 2. On the assembly drawings of harnesses, cables and wires, the remaining components should be depicted in a simplified way.
4. Shielded conductors should be depicted: simplified - as shown in Fig. 3;
conditionally - in accordance with the requirements given in GOST 2.721-74.
5. Ribbon, thread and other similar material, which should be wrapped around the harness or
cable, should not be depicted in the drawing; instructions on the material and its application should be given in technical requirements drawing.
6. The drawing of the bundle or cable must contain all the dimensions necessary for the manufacture of the product (Fig. 4).
When depicting a bundle on a scale of 1: 1, it is allowed to apply only the dimensions of the sections depicted with a gap (Fig. 5).
The dimensions of the bending radii may not be specified.
With a conditional image of the bundle, it is allowed to apply the dimensions of individual sections of the bundle without extension and dimension lines (Fig. 6).
7. The harness, which in the assembled product should be located in different planes (Fig. 7, a), should be depicted, as a rule, deployed in the plane of the drawing (Fig. 7, b). It is allowed to depict the tourniquet in axonometric projections.
8. Separate sections of the conductor image are allowed to be shifted as shown in Fig. eight.
9. When drawing a bundle on two or more sheets, the trunk of the bundle with all branches (groups of wires and individual wires) extending directly from the trunk should be depicted on the first sheet, preferably on a reduced scale. Branching groups of wires should be depicted in full in the form of remote elements (Fig. 9) on subsequent sheets of the drawing, preferably on a scale of 1:1 (Fig. 10).
The dimensions defining the position of the end ramifications, not shown on the first sheet, must be applied on the first and subsequent sheets, as shown in Fig. 9 and 10.
10. In the drawing of a bundle or cable, each conductor (wire of a bundle or cable core) must
have the designation assigned to it on the drawing for electrical installation, or in the absence of such a drawing, on the electrical wiring diagram of the product being mounted.
11. The conductor designation should be applied near both ends of the conductor image (Fig. 4, 9, 10) and, if necessary, at the branching points. It is allowed to apply the designation of the conductor on the image of the marking tag (Fig. 5).
12. On the harness drawing, it is allowed to assign a symbol to a group of conductors at the place of its branching into separate wires, while the groups should be designated capital letters Russian alphabet in alphabetical order in accordance with the arrangement of groups in the image, counting, as a rule, from top to bottom in the direction from left to right (Fig. 5).
13. On the images of connecting devices or near them, the designations assigned to these devices on the electrical circuit diagram of the product or on the connection diagram (Fig. 6) should be applied.
AT in cases where in the manufactured bundle (cable) the connecting devices should not be marked, it is allowed not to apply the markings on the drawing.
14. Instead of the image of the places of connection of conductors (wires of the bundle or cable cores), indications of connections can be given on the drawing of the bundle (cable) in the following ways:
in table, performed according to the rules given in GOST 2.413-72 (Sec. 2);
in connection table on the drawing field - on the first sheet of the drawing or its subsequent sheets;
in technical requirements of the drawing;
in form schematic representation on the drawing field.
15. When performing a table harness on the drawing according to the rules given in GOST 2.413-72 (section 2), it is allowed to replace the column "Wire" in it with the column "Return address" indicating in it the addresses of connection of the second ends of the wires. In this case, the connection table should not be shown on the drawing; the position numbers of the wires (material) according to the specification of the bundle must be marked on the image of the bundle or indicated in the technical requirements of the drawing. Designations of conductors in these cases may not be applied.
16. The connection table should be made in the form:
Conductor |
Accessions |
Note |
||
The dimensions of the columns of the table are not specified in this standard.
AT the column "Conductor" must indicate the designation of the conductor.
AT column "Pos." the position number of the material of the bundle wire according to the specification must be indicated.
AT in the column "Connections" the addresses of the connections of both ends of the conductor must be indicated. In cases where the end of the conductor is ferruled or left free, reference should be made to the position number or to an additional figure. In this case, it is allowed to refer to the designation assigned to the group of conductors in accordance with the requirements given in clause 12, for example: "A, pos ...".
AT the column "Length" must indicate the length of the wire bundle, if it is not indicated in the image.
It is allowed to include other columns in the connection table according to the relevant industry standard, if their content is not a repetition of the data available in other design documents (specifications, drawings, etc.).
17. In the technical requirements of the drawing, instructions on connections may be given in cases where the conductors connect the same-name contacts of the connecting devices to each other.
18. On the schematic representation of the wiring harness connections (Fig. 11), thin solid lines should be drawn, each of which represents, for example, a separate connector, identical lugs, free ends of conductors, etc. Wire (or jumper) connections should be indicated by connecting a solid main line (separately for each wire) to the corresponding thin lines or points of the schematic representation.
Wire pos. 30, except as otherwise noted.
The designations of the contacts of the connecting devices should be applied at the point indicating the connection, above or below the corresponding line. Above the line depicting the wire, the position number of the material of the wire according to the specification of the bundle must be applied.
Instructions for twisting wires can, if necessary, be given by the symbols given in GOST 2.721-74 or by text in the technical requirements of the drawing. It is allowed to indicate the position numbers of wire materials in the technical requirements of the drawing.
19. On the image of the bundle (cable), it is allowed not to put the position numbers of the lug tags, etc., if instructions for their installation are given in the technical requirements of the drawing or in the table of connections.
The ability to read electrical circuits is an important component, without which it is impossible to become a specialist in the field electrical work. Every novice electrician must know how sockets, switches, switching devices and even an electricity meter are indicated on the wiring project in accordance with GOST. Next, we will provide readers of the site with symbols in electrical circuits, both graphic and alphabetic.
Graphic
As for the graphic designation of all the elements used in the diagram, we will provide this overview in the form of tables in which the products will be grouped according to their purpose.
In the first table you can see how electrical boxes, boards, cabinets and panels are marked on the wiring diagrams:
The next thing you should know is the symbol for power sockets and switches (including walk-throughs) on single-line diagrams of apartments and private houses:
As for lighting elements, fixtures and lamps according to GOST are indicated as follows:
In more complex schemes where electric motors are used, elements such as:
It is also useful to know how transformers and chokes are graphically indicated on circuit diagrams:
Electrical measuring instruments according to GOST have the following graphic designation in the drawings:
And here, by the way, is a table useful for beginner electricians, which shows how the ground loop looks on the wiring plan, as well as the power line itself:
In addition, on the diagrams you can see a wavy or straight line, “+” and “-”, which indicate the type of current, voltage and pulse shape:
In more complex automation schemes, you may encounter incomprehensible graphic symbols, like contact connections. Remember how these devices are indicated on the wiring diagrams:
In addition, you should be aware of how radio elements look on projects (diodes, resistors, transistors, etc.):
That's all conditionally graphic designations in electrical circuits of power circuits and lighting. As you yourself have already seen, there are quite a lot of components and you can remember how each is designated only with experience. Therefore, we recommend that you save all these tables for yourself, so that when reading the wiring layout of a house or apartment, you can immediately determine what kind of circuit element is in a certain place.
Interesting video
Reading schemes is impossible without knowledge of the conditional graphic and letter designations of elements. Most of them are standardized and described in normative documents. Most of them were published in the last century and new standard only one was adopted, in 2011 (GOST 2-702-2011 ESKD. Rules for the execution of electrical circuits), so sometimes a new element base is designated according to the principle “how someone came up with it”. And this is the difficulty of reading the schemes of new devices. But, basically, the symbols in electrical circuits are described and are well known to many.
Two types of designations are often used on diagrams: graphic and alphabetic, and denominations are also often put down. According to these data, many can immediately tell how the scheme works. This skill develops over years of practice, but first you need to understand and remember the symbols in electrical circuits. Then, knowing the work of each element, you can imagine the final result of the device.
Drawing up and reading various diagrams usually requires different elements. There are many types of circuits, but in electrics the following are commonly used:
There are many other types of electrical circuits, but they are not used in home practice. An exception is the cable route through the site, the supply of electricity to the house. This type of document will definitely be needed and useful, but it's more of a blueprint than an outline.
Basic images and functional features
Switching devices (switches, contactors, etc.) are built on contacts of various mechanics. There are make, break, changeover contacts. The closing contact is open in the normal state, when it is switched to the working state, the circuit closes. The NC contact is normally closed, but when certain conditions it works by opening the circuit.
The changeover contact can be two or three positions. In the first case, one circuit works, then another. The second has a neutral position.
In addition, contacts can perform different functions: contactor, disconnector, switch, etc. All of them also have a symbol and are applied to the corresponding contacts. There are functions that only moving contacts perform. They are shown in the photo below.
The main functions can only be performed by fixed contacts.
Symbols for single-line diagrams
As already mentioned, only the power part is indicated on single-line diagrams: RCDs, automata, difautomats, sockets, knife switches, switches, etc. and connections between them. The designations of these conditional elements can be used in electrical panel diagrams.
The main feature of graphic symbols in electrical circuits is that devices similar in principle of operation differ in some trifle. For example, an automatic machine (circuit breaker) and a knife switch differ only in two small details- the presence / absence of a rectangle on the contact and the shape of the icon on the fixed contact, which display the functions of these contacts. The only difference between a contactor and a knife switch is the shape of the icon on the fixed contact. A very small difference, but the device and its functions are different. All these little things need to look closely and remember.
Also, a small difference between the RCD symbols and differential automaton. It is also only in the functions of moving and fixed contacts.
The situation is approximately the same with the coils of relays and contactors. They look like a rectangle with small graphic additions.
In this case, it is easier to remember, since there are quite serious differences in appearance additional icons. With a photorelay, it’s quite simple - the rays of the sun are associated with arrows. The impulse relay is also quite easy to distinguish by the characteristic shape of the sign.
A little easier with lamps and connections. They have different "pictures". plug connection(like a socket / plug or socket / plug) looks like two brackets, and a collapsible one (like a terminal block) looks like circles. Moreover, the number of pairs of checkmarks or circles indicates the number of wires.
Image of tires and wires
In any scheme, connections are appropriate and for the most part they are made by wires. Some connections are tires - more powerful conductor elements, from which taps can extend. Wires are indicated by a thin line, and branch / connection points are indicated by dots. If there are no dots, this is not a connection, but an intersection (without an electrical connection).
There are separate images for buses, but they are used if it is necessary to separate them graphically from communication lines, wires and cables.
On the wiring diagrams often it is necessary to indicate not only how the cable or wire passes, but also its characteristics or installation method. All this is also displayed graphically. To read the drawings, this is also necessary information.
How switches, switches, sockets are depicted
There are no images approved by standards for some types of this equipment. So, dimmers (dimmers) and push-button switches remained without designation.
But all other types of switches have their own symbols in electrical circuits. They are open and hidden installation, respectively, there are also two groups of icons. The difference is the position of the dash on the key image. In order to understand on the diagram what type of switch we are talking about, this must be remembered.
There are separate designations for two-gang and three-gang switches. In the documentation, they are called "double" and "triple", respectively. There are differences for cases with varying degrees protection. In rooms with normal conditions operation put switches with IP20, maybe up to IP23. In wet rooms(bathroom, swimming pool) or outdoors, the degree of protection must be at least IP44. Their images differ in that the circles are filled in. So it's easy to tell them apart.
There are separate images for switches. These are switches that allow you to control the on / off of the light from two points (there are also three, but without standard images).
The same trend is observed in the designations of sockets and socket groups: there are single, double sockets, there are groups of several pieces. Products for rooms with normal operating conditions (IP from 20 to 23) have an unpainted middle, for wet rooms with increased protection (IP44 and above) the middle is tinted in a dark color.
Symbols in electrical circuits: sockets different type installation (open, hidden)
Having understood the logic of the designation and remembering some initial data (what is the difference conditional image sockets of open and hidden installation, for example), after a while you will be able to confidently navigate the drawings and diagrams.
Luminaires on the diagrams
This section describes the conventions in electrical diagrams. various lamps and lamps. Here the situation with the designations of the new element base is better: there are even signs for LED lamps and fixtures, compact fluorescent lamps (housekeepers). It is also good that the images of lamps of different types are significantly different - it is difficult to confuse. For example, lamps with incandescent lamps are depicted in the form of a circle, with long linear fluorescent lamps - a long narrow rectangle. The difference in the image of a linear lamp of a fluorescent type and an LED is not very big - only dashes at the ends - but even here you can remember.
The standard even has symbols in electrical diagrams for ceiling and hanging lamp(cartridge). They also have quite unusual shape- circles of small diameter with dashes. In general, this section is easier to navigate than others.
Elements of circuit diagrams
Schematic diagrams of devices contain another element base. Communication lines, terminals, connectors, light bulbs are also shown, but, in addition, there is a large number of radio elements: resistors, capacitors, fuses, diodes, thyristors, LEDs. Most of the symbols in the electrical circuits of this element base are shown in the figures below.
More rare ones will have to be looked for separately. But most circuits contain these elements.
Letter symbols in electrical circuits
In addition to graphic images, the elements on the diagrams are signed. It also helps to read diagrams. Next to the letter designation of the element is often its serial number. This is done so that later it was easy to find the type and parameters in the specification.
The table above shows international designations. There is also a domestic standard - GOST 7624-55. Extracts from there with the table below.
To understand what is specifically drawn on a diagram or drawing, you need to know the decoding of those icons that are on it. This recognition is also called drawing reading. And to facilitate this lesson, almost all elements have their own conditional icons. Almost, because the standards have not been updated for a long time and some elements are drawn by everyone as best they can. But, for the most part, symbols in electrical circuits are in regulatory documents.
Symbols in electrical circuits: lamps, transformers, measuring instruments, main element base
Normative base
There are about a dozen types of electrical circuits, the number various elements, which can be found there, is in the tens, if not hundreds. To facilitate the recognition of these elements, uniform symbols have been introduced in electrical circuits. All rules are written in GOSTs. There are a lot of these standards, but the main information is in the following standards:
Studying GOSTs is a useful thing, but it takes time, which not everyone has enough of. Therefore, in the article we present the symbols in electrical circuits - the main element base for creating drawings and wiring diagrams, circuit diagrams of devices.
Some experts, having carefully looked at the circuit, can say what it is and how it works. Some may even issue possible problems that may occur during operation. It's simple - they know the circuitry and the element base well, and are also well versed in the symbols of the circuit elements. Such a skill has been developed over the years, and, for "dummies", it is important to remember the most common ones to begin with.
Electrical panels, cabinets, boxes
On the power supply diagrams of a house or apartment, there will necessarily be a designation or a cabinet. In apartments, the terminal device is mainly installed there, since the wiring does not go further. In houses, they can design the installation of a branching electrical cabinet - if a route goes from it to illuminate other buildings located at some distance from the house - baths, guest house. These other designations are in the next picture.
If we talk about images of the "stuffing" of electrical panels, it is also standardized. There are symbols for RCDs, circuit breakers, buttons, current and voltage transformers, and some other elements. They are shown in the following table (there are two pages in the table, scroll by clicking on the word "Next")
| Number | Name | Image on the diagram |
|---|---|---|
| 1 | Circuit breaker (automatic) |  |
| 2 | Knife switch (load switch) |  |
| 3 | Thermal relay (overheating protection) |  |
| 4 | RCD (residual current device) |  |
| 5 | Differential automaton (difavtomat) |  |
| 6 | Fuse | |
| 7 | Switch (knife switch) with fuse |  |
| 8 | Circuit breaker with built-in thermal relay (for motor protection) |  |
| 9 | Current transformer |  |
| 10 | voltage transformer |  |
| 11 | electricity meter |  |
| 12 | A frequency converter |  |
| 13 | Button with automatic opening of contacts after pressing |  |
| 14 | Button with contact opening when pressed again |  |
| 15 | Button with a special switch to disable (stop, for example) |  |
Element base for wiring diagrams
When drawing up or reading a diagram, the designations of wires, terminals, grounding, zero, etc. will also come in handy. This is what a novice electrician simply needs or in order to understand what is shown in the drawing and in what sequence its elements are connected.
| Number | Name | Designation electrical elements on the diagrams |
|---|---|---|
| 1 | Phase conductor |  |
| 2 | Neutral (zero working) N |  |
| 3 | Protective conductor ("earth") PE |  |
| 4 | Combined protective and neutral conductors PEN |  |
| 5 | Electric communication line, busbars |  |
| 6 | Bus (if it needs to be selected) |  |
| 7 | Busbar taps (made by soldering) |  |
An example of the use of the above graphics is in the following diagram. Thanks to the letter designations, everything is clear even without graphics, but duplication of information in the diagrams has never been superfluous.
Picture of sockets
On the wiring diagram, the installation locations of sockets and switches should be marked. There are many types of sockets - 220 V, 380 V, hidden and open type installations, with different amount"seating" seats, waterproof, etc. To give the designation of each is too long and useless. It is important to remember how the main groups are depicted, and the number of contact groups is determined by the strokes.
Designation of sockets in the drawings
Sockets for a single-phase 220 V network are indicated on the diagrams in the form of a semicircle with one or more segments sticking up. The number of segments is the number of sockets on one housing (illustrated in the photo below). If only one plug can be plugged into the outlet, one segment is drawn up, if two, two, etc.
If you look at the images closely, notice that the symbolic image on the right does not have the horizontal bar that separates the two halves of the icon. This feature indicates that the socket concealed installation, that is, under it it is necessary to make a hole in the wall, install a socket box, etc. The option on the right is for open mounting. A non-conductive substrate is attached to the wall, and the socket itself is attached to it.
Also note that the bottom of the left schematic is crossed out with a vertical line. This indicates the presence of a protective contact, to which grounding is applied. The installation of sockets with grounding is mandatory when turning on a complex household appliances type washing or, oven, etc.
You can’t confuse the symbol of a three-phase socket (for 380 V) with anything. The number of segments sticking up is equal to the number of conductors that are to this device connected - three phases, zero and earth. Total five.
It happens that the lower part of the image is painted over with black (dark). This means that the outlet is waterproof. These are placed on the street, in rooms with high humidity(baths, pools, etc.).
Switch display
The schematic designation of the switches looks like small size a circle with one or more L- or T-shaped branches. Branches in the form of the letter "G" designate an open-mounted switch, with the form of the letter "T" - flush-mounted. The number of taps displays the number of keys on this device.
In addition to the usual ones, they can stand - to be able to turn on / off one light source from several points. Two letters "G" are added to the same small circle from opposite sides. This is the designation of a single-key pass-through switch.
Unlike conventional switches, in these, when using two-button models, one more bar is added parallel to the top one.
Lamps and fixtures
Lamps have their own designations. And the lamps are different. daylight(fluorescent) and incandescent lamps. The diagrams even show the shape and size of the fixtures. In this case, you just need to remember how each type of lamp looks on the diagram.
Radioelements
When reading circuit diagrams of devices, you need to know the symbols for diodes, resistors, and other similar elements.
Knowing the conditional graphic elements will help you read almost any diagram - some kind of device or electrical wiring. The ratings of the required parts are sometimes affixed next to the image, but in large multi-element diagrams they are written in a separate table. They stand in it letter designations circuit elements and ratings.
Letter designations
In addition to the fact that the elements on the diagrams have conditional graphic names, they have letter designations, which are also standardized (GOST 7624-55).
| Name of electrical circuit element | Letter designation | |
|---|---|---|
| 1 | Switch, controller, switch | AT |
| 2 | Electric generator | G |
| 3 | Diode | D |
| 4 | Rectifier | Vp |
| 5 | Sound alarm (bell, siren) | Sv |
| 6 | Button | Kn |
| 7 | incandescent lamp | L |
| 8 | Electrical engine | M |
| 9 | Fuse | Etc |
| 10 | Contactor, magnetic starter | To |
| 11 | Relay | R |
| 12 | Transformer (autotransformer) | Tr |
| 13 | plug connector | W |
| 14 | Electromagnet | Em |
| 15 | Resistor | R |
| 16 | Capacitor | With |
| 17 | Inductor | L |
| 18 | Control button | Ku |
| 19 | Terminal switch | Kv |
| 20 | Throttle | dr |
| 21 | Telephone | T |
| 22 | Microphone | Mk |
| 23 | Speaker | Gr |
| 24 | Battery (galvanic cell) | B |
| 25 | Main engine | Dg |
| 26 | Cooling pump motor | Before |
Please note that in most cases Russian letters are used, but the resistor, capacitor and inductor are indicated in Latin letters.
There is one subtlety in the designation of the relay. They are of different types, respectively marked:
- current relay - RT;
- power - RM;
- voltage - PH;
- time - RV;
- resistance - RS;
- index - RU;
- intermediate - RP;
- gas - RG;
- with time delay - RTV.
Basically, these are only the most conventional symbols in electrical circuits. But most of the drawings and plans you can now understand. If you need to know images of rarer elements, study GOSTs.
If for ordinary person the perception of information occurs when reading words and letters, then for locksmiths and installers they are replaced by alphabetic, numeric or graphic symbols. The difficulty is that while the electrician graduates, gets a job, learns something in practice, as new SNiPs and GOSTs appear, according to which adjustments are made. Therefore, do not try to learn all the documentation and immediately. It is enough to gain basic knowledge, and add up-to-date data in the course of working days.
For circuit designers, instrumentation and automation fitters, electricians, the ability to read an electrical circuit - key quality and qualification score. Without special knowledge, it is impossible to immediately understand the intricacies of designing devices, circuits and methods of connecting electrical components.
Types and types of electrical circuits
Before you start studying the existing designations of electrical equipment and its connections, you need to understand the typology of circuits. On the territory of our country, standardization was introduced in accordance with GOST 2.701-2008 of July 1, 2009, according to “ESKD. Scheme. Types and types. General requirements».
Based on this standard, all schemes are divided into 8 types:
- United.
- Located.
- General.
- Connections.
- Mounting connections.
- Complete principal.
- Functional.
- Structural.
Among the existing 10 species indicated in this document, there are:
- Combined.
- divisions.
- Energy.
- Optical.
- Vacuum.
- Kinematic.
- Gas.
- Pneumatic.
- Hydraulic.
- Electrical.
For electricians, it is of the greatest interest among all the above types and types of circuits, as well as the most popular and frequently used in work - the electrical circuit.
The latest GOST, which came out, is supplemented by many new designations, relevant today with the code 2.702-2011 of 01/01/2012. The document is called "ESKD. Rules for the implementation of electrical circuits ”, refers to other GOSTs, among which are those mentioned above.
The text of the regulation sets out clear requirements in detail for electrical circuits of all types. Therefore, be guided by installation work with electrical circuits follows exactly this document. The definition of the concept of an electrical circuit, according to GOST 2.702-2011, is as follows:
"Under the electrical circuit should be understood a document containing the symbols of the parts of the product and / or individual parts with a description of the relationship between them, the principles of operation from electrical energy."
After the definition, the document contains the rules for the implementation on paper and in software environments of the designations of contact connections, wire marking, lettering and graphic representation of electrical elements.
It should be noted that more often in home practice only three types of electrical circuits are used:
- Mounting- for the device is displayed printed circuit board with the arrangement of elements with a clear indication of the place, denomination, the principle of fastening and leading to other details. Wiring diagrams for residential premises indicate the number, location, rating, connection method and other precise instructions for installing wires, switches, lamps, sockets, etc.
- Fundamental- they indicate in detail the connections, contacts and characteristics of each element for networks or devices. Distinguish between full and linear circuit diagrams. In the first case, control, control of elements and the power circuit itself are depicted; in a linear scheme, they are limited only to a chain with the image of the remaining elements on separate sheets.
- Functional- here, without detailing the physical dimensions and other parameters, the main components of the device or circuit are indicated. Any detail can be represented as a block with a letter designation, supplemented with links to other elements of the device.
Graphic symbols in electrical circuits
Documentation, which indicates the rules and methods for graphic designation of circuit elements, is represented by three GOSTs:
- 2.755-87 - graphic symbols for contact and switching connections.
- 2.721-74 - graphic symbols for parts and assemblies of general use.
- 2.709-89 - graphic symbols in electrical diagrams of circuit sections, equipment, contact connections of wires, electrical elements.
In the standard with the code 2.755-87, it is used for diagrams of single-line electrical panels, conditional graphic images (UGO) of thermal relays, contactors, knife switches, circuit breakers, and other switching equipment. There is no designation in the standards of difavtomatov and RCD.
On the pages of GOST 2.702-2011, the image of these elements is allowed in an arbitrary order, with explanations, decoding of the UGO and the circuit of difavtomatov and RCD itself.
GOST 2.721-74 contains UGOs used for secondary electrical circuits.
IMPORTANT: To designate switching equipment, there is:
4 base images UGO
9 functional signs of UGO
| UGO | Name |
| Arc quenching | |
| No self-return | |
| self-return | |
| Limit or travel switch | |
| With automatic actuation | |
| switch-disconnector | |
| Disconnector | |
| Switch | |
| Contactor |
IMPORTANT: Designations 1 - 3 and 6 - 9 are applied to fixed contacts, 4 and 5 are placed on moving contacts.
Basic UGOs for single-line electrical switchboard diagrams
| UGO | Name |
| Thermal relay | |
| contactor contact | |
| Knife switch - load switch | |
| Automatic - automatic switch | |
| Fuse | |
| Differential circuit breaker | |
| RCD | |
| voltage transformer | |
| Current transformer | |
| Knife switch (load switch) with fuse | |
| Motor protection circuit breaker (with built-in thermal relay) | |
| A frequency converter | |
| electric meter | |
| Normally open contact with "reset" button or other push-button switch, with reset and opening by means of a special drive of the control element | |
| Normally open contact with pushbutton, with reset and opening by retracting the button of the operating element | |
| Normally open contact with pushbutton, with reset and opening by repeated pressing of the button of the operating element | |
| Normally open contact with pushbutton, with reset and automatic opening of the operating element | |
| N/O contact with delayed action, which is initiated on return and operation | |
| N/O contact with delayed action, which is initiated only when triggered | |
| Slow-acting make contact that is activated on return and trip | |
| N/O contact with delayed action that only trips on return | |
| N/O contact with delayed action that only closes when triggered | |
| Timing relay coil | |
| photorelay coil | |
| Pulse relay coil | |
| General designation of a relay coil or contactor coil | |
| Indicator lamp (light), lighting | |
| motor drive | |
| Terminal (collapsible connection) | |
| Varistor, surge arrester (surge arrester) | |
| Discharger | |
Socket (plug connection):
|
|
| A heating element |
Designation of electrical measuring instruments for characterizing circuit parameters
GOST 2.271-74 adopted the following designations in electrical panels for tires and wires:
Letter designations in electrical circuits
The standards for the letter designation of elements on electrical diagrams are described in the GOST 2.710-81 standard with the title of the text “ESKD. Alphanumeric designations in electrical circuits. The mark for difavtomatov and RCD is not indicated here, which is prescribed in clause 2.2.12 of this standard as a designation with multi-letter codes. The following letter codings are accepted for the main elements of electrical panels:
| Name | Designation |
| Automatic switch in the power circuit | QF |
| Automatic switch in the control circuit | SF |
| Circuit breaker with differential protection or difavtomat | QFD |
| Breaker or load switch | QS |
| RCD (residual current device) | QSD |
| Contactor | KM |
| Thermal relay | F, KK |
| Time relay | KT |
| Voltage relay | KV |
| impulse relay | KI |
| photorelay | KL |
| OPN, arrester | FV |
| fuse | FU |
| voltage transformer | TV |
| Current transformer | TA |
| A frequency converter | USD |
| Ammeter | PA |
| Wattmeter | PW |
| Frequency meter | PF |
| Voltmeter | PV |
| Active energy meter | PI |
| Reactive energy meter | PK |
| heating element | EK |
| Photocell | BL |
| lighting lamp | EL |
| Light bulb or indicator light | HL |
| Plug connector or socket | XS |
| Switch or circuit breaker in control circuits | SA |
| Pushbutton switch in control circuits | SB |
| Terminals | XT |
Image of electrical equipment on the plans
Despite the fact that GOST 2.702-2011 and GOST 2.701-2008 take into account such a type of electrical circuit as a "layout" for the design of structures and buildings, it is necessary to be guided by the standards of GOST 21.210-2014, which indicate "SPDS.
Images on the plans of conditional graphic wiring and electrical equipment. The document establishes UGO on plans for laying electrical networks of electrical equipment (lamps, switches, sockets, electrical panels, transformers), cable lines, busbars, tires.
The use of these symbols is used to draw up drawings of electrical lighting, power electrical equipment, power supply and other plans. The use of these designations is also used in the schematic single-line diagrams of electrical panels.
Conditional graphic images of electrical equipment, electrical devices and electrical receivers
The contours of all depicted devices, depending on the information richness and complexity of the configuration, are taken in accordance with GOST 2.302 on the scale of the drawing according to the actual dimensions.
Conditional graphic designations of wiring lines and conductors
Conditional graphic images of tires and busbars
IMPORTANT: The design position of the bus duct must exactly match on the diagram with the place of its attachment.
Conditional graphic images of boxes, cabinets, shields and consoles
Conditional graphic symbols of switches, switches
On the pages of the GOST 21.210-2014 documentation for push-button switches, dimmers (dimmers), a separate designation is not provided. In some schemes, according to clause 4.7. normative act, arbitrary designations are used.
Conventional graphic designations of socket outlets
Conditional graphic designations of lamps and spotlights
The updated version of GOST contains images of luminaires with fluorescent and LED lamps.
Conditional graphic designations of control and management devices
Conclusion
The given graphic and letter images of electrical components and electrical circuits are not complete list, since the regulations contain many special characters and ciphers that are practically not used in everyday life. To read electrical circuits, you will need to take into account many factors, first of all, the country of the manufacturer of the device or electrical equipment, wiring and cables. There is a difference in marking and symbol on the diagrams, which can be quite confusing.
Secondly, you should carefully consider such areas as the intersection or lack of a common network for wires located with an overlay. On the foreign schemes if the bus or cable does not have a common power supply with intersecting objects, a semicircular continuation is drawn at the point of contact. This is not used in domestic schemes.
If the diagram is depicted without complying with the standards established by GOSTs, then it is called a sketch. But for this category there are also certain requirements, according to which, according to the above sketch, an approximate understanding of the future electrical wiring or device design should be drawn up. Drawings can be used to draw up more accurate drawings and diagrams from them, with the necessary designations, markings and scales.